1. Field of the Invention
This invention relates generally to tripod stands, and more particularly to an adjustable tripod stand for supporting various articles which has independently adjustable movable legs.
2. Brief Description of the Prior Art
Because of their size, weight, portability and ease and speed of deployment, tripod stands are desirable for supporting various articles and instruments since they provide selective height adjustment and a stable support. They are particularly useful is supporting such things as cameras, video equipment, telescopes, surveying instruments, and musical instruments.
Some tripod stands have legs which may be adjusted in length to maintain the supported article in a level position on uneven ground but the legs are not independently adjustable relative to one another and to the vertical support member, thus the center of gravity may be off-axis. In other words, the vertical portion of the stand cannot be oriented in an off-axis position and still maintain the center of gravity for a stable support system.
Another problem with conventional tripod stands is that the legs are not particularly suited for reducing the perimeter of the support base and still provide a stable support system when placing the legs in close or confined areas and on multi-level surfaces.
There are several patents which describe various adjustable tripod stand devices.
Viken, U.S. Pat. No. 1,795,747 discloses a tripod having collapsible legs with an extensible support composed of three telescoping members slidably supported by the legs.
Bogar, U.S. Pat. No. 3,307,814 discloses a stand for instruments of the type having a box-like casing. The stand has telescopically adjustable legs or vertical tubular upright members and a tray at the top of the uprights.
Boehm, U.S. Pat. No. 3,570,130 discloses a holding device for surveying instruments which includes a channel-like mounting bracket with a pair of instrument gripping clamps and a pair of adjustable legs thereon which cooperate with the instrument to form a tripod type support for supporting the instrument in a reference position.
The present invention is distinguished over the prior art in general, and these patents in particular by an adjustable tripod stand with independently adjustable legs which comprises a longitudinal extensible upright portion of telescoping tubular members, a plurality of collar members slidably mounted on the upright portion which are longitudinally adjustable relative to one another and to the upright portion for selective positioning thereon, and a plurality of movable leg members are operatively connected to upper and lower collar members for selective independent longitudinal positioning and radial extension relative to the upright portion and to one another.
When the upper leg supporting collar and the corresponding lower collar are moved toward each other on the upright portion, the bottom of the leg connected thereto will be extended radially outward to be positioned an unequal distance from the center of the upright portion relative to the other legs, and the upper leg supporting collar and the corresponding lower collar are moved away from each other, the bottom of the leg connected thereto will be drawn radially inward to be positioned an unequal distance from the center of the upright portion relative to the other legs. The independent positioning of the legs allows the stand to be erected in limited or confined areas or on multi-level surfaces. The independent positioning of the legs also allows the longitudinal axis of the stand to be disposed in an off-vertical axis position for positioning the center of gravity of the supported article relative to the center of the supporting legs.